videoconferencing standards

Following are the primary standards used with videoconferencing. See videoconferencing.

Videophone Directory
H.350 is the ITU standard for a videophone directory. See H.350.

Session Initiation for Dial-Up Networks and T1
H.320 is the ITU standard for dial-up ISDN, fractional T1 and Switched 56 services. H.324 is used with regular phone lines and analog modems. See H.320 and H.324.

Session Initiation for IP Networks
H.323 is the ITU standard for voice and video over packet networks, which today means IP LANs and the public Internet. SIP is the IETF standard for voice and video over IP. MCUs may handle H.323 clients only or both H.323 and SIP clients. Most traditional IP video clients are H.323, but SIP is gaining ground. See H.323 and SIP.

Compression: H.263 and H.264
The primary ITU codecs for compressing video are H.263 and H.264, the latter halving the bandwidth requirement of the former. See H.263 and H.264.

Data Conferencing: T.120
T.120 is the ITU standard for whiteboards, application sharing and application viewing, all of which can be used with or without videoconferencing. Earlier systems mixed data conferencing and video streams together, but newer ones keep T.120 tools separate in order not to sacrifice video quality. Using standard PCs and the Internet for data collaboration is more than adequate. Some vendors support their own proprietary IP-based data collaboration, such as VCON does with its IPNexus system. See whiteboard and application sharing.

Dual Streams
Dual streams allows bandwidth to be split between regular video and another video stream, including output from a VCR, camera or PC screen. The second stream may be screen data, but there is no interaction as with collaborative tools. TANDBERG calls its dual streams Duo Video.